Attention is being given to an imprint technology of molding a resin (imprint material) on a substrate by using the pattern of a mold (a mold, an original, a mask) and forming a resin pattern on the substrate (such as a wafer or a glass substrate). This technology enables a fine structure on the order of a few nanometers to be created on a substrate. Examples of an imprint technology include a photo-curing method, a thermal-curing method, and a sol-gel imprint method. For example, an imprint apparatus employing the photo-curing method applies an ultraviolet curable resin (an imprint resin, a photo-curable resin) to a shot area (imprint area) on a substrate. Then, the uncured resin is molded by using a mold. After ultraviolet rays are emitted so that the resin is cured, the mold is released, whereby a resin pattern is formed on the substrate.
In Japanese Patent Laid-Open No. 2004-103817, an imprint apparatus is disclosed which uses condensable gas that is condensed and liquefied by a pressure rise (compression) occurring when a mold is pressed against a resin in an imprint atmosphere. When the condensable gas is liquefied, the volume is reduced to several hundredth of that produced when the condensable gas remains in gaseous form. Therefore, an effect which affects pattern formation and which is produced by residual gas between the mold and the substrate which are pressed against each other may be suppressed.
The following state has been found. In imprint processing in the atmosphere containing condensable gas, the condensate liquid having been absorbed into the resin is desorbed from the resin to the outside after completion of the pressing. Therefore, the pattern formed on the substrate may shrink, so that the pattern shape is degraded. For example, pattern line widths are reduced, the degree of roughness of the surface becomes larger, and/or the pattern shape is deformed into a shape which is not a rectangle.
An object of the present invention is to form a pattern on a substrate with accuracy higher than that in the related art, in imprint processing in an atmosphere containing condensable gas.